[FIR] Add NOT_A_CLASS diagnostics

compiler/testData/diagnostics/tests/annotations/typeParameterAsAnnotation.fir.kt

@@ -1,9 +0,0 @@
-class Foo<T> {
-    @T
-    fun foo() = 0
-}
-
-class Bar<T : Annotation> {
-    @T
-    fun foo() = 0
-}

compiler/testData/diagnostics/tests/annotations/typeParameterAsAnnotation.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 class Foo<T> {
     @<!NOT_A_CLASS!>T<!>
     fun foo() = 0